1. Field of the Invention
The present invention relates to, but is not limited to, electronic devices, and in particular, to the field of electronic device manufacturing.
2. Description of Related Art
In the current field of semiconductor manufacturing, a photolithography process is often used to form a photoresist pattern on a substrate of a die or a wafer. The resulting photoresist pattern may be used to etch circuitry and/or electronic component features onto the substrate.
In brief, a photolithography process typically involves initially depositing a photoresist composition on top of the substrate to form a photoresist film on the substrate. A patterning mask is then placed on top of the photoresist film leaving certain portions of the photoresist film exposed while leaving other portions unexposed. The exposed portions may then be exposed to an electromagnetic radiation source (e.g., light source) that generates electromagnetic radiation of specific wavelength or range of wavelengths in order to initiate chemical reactions within the exposed portions of the photoresist film.
As a result of these reactions, the exposed portions become either removable or not removable (depending on whether the photoresist film is a positive or negative type photoresist) in subsequent processes such as a wash process that may further include separate develop and rinse processes. For lack of a better term and for purposes of this description, the process of exposing the photoresist film to the electromagnetic radiation will be called an “exposure curing” process. After the completion of the exposure curing process, the wash process may be performed in order to remove the removable portions of the photoresist film. As a result, a photoresist pattern is formed on top of the substrate.
The formed photoresist pattern, in turn, may be subsequently used as an etching mask in order to form circuitry and/or electronic component features on the substrate. Although not described above, additional procedures such as baking and/or heating procedures may also be performed during the various stages of the photoresist patterning process.
Typically the formulation of a photoresist composition used for a photolithography process may vary depending on various design criteria. That is, the formulation of a photoresist composition may depend on the size of the circuitry or electronic components being formed or patterned. As circuitry and electronic components become smaller, the formulation of the photoresist composition will likewise change in order to meet the changing manufacturing requirements for producing the circuitry features used to form these smaller components. For example, if a via or a trace is being formed then the formulation of the photoresist composition may depend upon the size, such as the node width, of the via or the trace being formed. Each of the photoresist composition formulations is typically identified by the wavelength of the corresponding electromagnetic radiation (e.g., light) used to exposure cure the photoresist. For example, a photoresist composition may be identified as 365 nanometer (nm) photoresist (I-line), a 248 nm photoresist (called deep UV or DUV), a 193 nm photoresist, 157 nm photoresist, and the like. Commercial suppliers typically sell these photoresist types.
As electronic components have become smaller, one problem faced by semiconductor device manufacturers is the problem of pattern collapse or photoresist pattern collapse. It has been proposed that pattern collapse occurs as a result of the photoresist development process when a developer solution or rinse solution (DI water) “pulls down” the photoresist lines. In order to avoid such problems, it is known to add surfactants to the developer or rinse solutions to reduce collapse. However, such solutions may have certain drawbacks.